Volume-18-Issue 2 (2021)
Latest Articles
A shelf-life model considering mechanical injury and natural decay to optimize fresh fruit distribution
IJTEE, Volume-18, Issue 2 (2021) , PP 89 - 99
Published: 02 Sep 2021
DOI: 10.5383/ijtee.18.02.005
by Damrongpol Kamhangwong, Aicha Sekhari, Gilles Neubert from Université Lumière Lyon 2, Lyon, France and Emlyon Business School, Saint-Étienne, France.
Abstract: This paper develops a specific quality attribute model considering mechanical injury (MI) and natural decay (ND) in fresh fruit, for problem solving in operations research. The model resolves shortcomings found in the widely adopted models mainly focused on a set or an undetermined shelf life, through a multi-objective framework designed to study the economic benefits of fresh fruit distribution. The multi-objective optimization model integrates the transportation and inventory planning of fresh fruit (MOTIP). It is based on a bi-objective function maximizing the total net profit (NP) and the percentage of the remaining fruit quality (%RQ), using a Non-Dominated Sorting Genetic Algorithm II (NSGA-II) to solve the problem. The results indicate the accuracy of NSGA-II algorithm to solve the problem of fresh fruit distribution. The optimal Pareto front curves of the TIP model show a strong positive correlation between the %RQ and the NP. While the specific kinetic shelf-life model can be used to decide on the best schedule for transporting and storing fruit in order to optimize the net profit and remaining quality, the MOTIP-model allows a significant improvement in the benefits related to the export of fresh fruit while minimizing the loss of quality. The developed model is a decision support tool that allows exporters to better plan the transport and storage of exported fresh fruits. read more... read less...
Keywords: fresh fruit quality; fresh fruit distribution; shelf-life model; quality loss; multi-objective decision-making
Numerical simulation of multiphase flow at fracture intersections
IJTEE, Volume-18, Issue 2 (2021) , PP 79 - 88
Published: 02 Sep 2021
DOI: 10.5383/ijtee.18.02.004
by Wenjuan Zhang, Isam Janajreh, Mohammed Al Kobaisi from Department of petroleum engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE and Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE
Abstract: Various models of simulating immiscible multiphase flow in a simple fracture intersection is compared numerically in this work. The first two models assume that the fractures can be treated as a type of porous media and fluid flow in fractures is therefore governed by Darcy’s law. The fractures are either gridded explicitly (equal-dimensional porous fracture model) to account for the fracture intersection or they are simplified as lower-dimensional entities (lower-dimensional porous fracture model) and fracture intersection is eliminated in the computational domain by using the star-delta transformation. Numerical results of equal-dimensional porous fracture model demonstrate that fracture intersection angle and the scale ratio of fracture length to fracture aperture can impact the multiphase flow behavior at fracture intersections but the effects of these factors cannot be captured by the lower-dimensional porous fracture model. A CFD study is then conducted to gain better insight into the problem by solving the Navier-Stokes equation coupled with Volume of Fluid (VOF) method. The results show that viscosity of the two phases can affect flow at the fracture intersection. When the two phases have the same viscosity, the equal-dimensional porous fracture model agrees qualitatively with CFD results but the porous fracture model is much more sensitive to viscosity contrast than what is predicted by CFD simulation. read more... read less...
Keywords: Fracture modeling, Darcy’s law,Navier-Stokes equation, volume of fluid
Comparative Life Cycle Assessment of Paper and Computer Based Exams
IJTEE, Volume-18, Issue 2 (2021) , PP 71 - 77
Published: 02 Sep 2021
DOI: 10.5383/ijtee.18.02.003
by Muhammad Imran, Salah Elaskari, Abdulmajeed Eid Albalawi from University of Tabuk, Tabuk, Saudi Arabia, 71491 and American International University, Al Jahra, Kuwait
Abstract: Universities around the globe consume large number of papers every year for educational and administrative purposes. A major portion of these papers are consumed for exam purpose only. Post Covid -19, several universities have moved to computer-based exams because of health and safety concerns. The purpose of this article is to compare paper and computer-based exams primarily from the perspective of their impact on the environment. Our main aim is to perform Life Cycle Assessment (LCA) for three scenarios and find out which one of them is better from the environmental perspective. The three scenarios that have been considered for LCA modelling are as follows: (1) consumed papers go to landfill, (2) consumed papers are recycled, and (3) switching to computer-based exams. The procedure of conducting the LCA follows the ISO 14040 standard method which consists of four steps: (1) goal and scope definition, (2) inventory analysis, (3) impact assessment and (4) interpretation. This research uses GaBi educational software tool for LCA modeling and considers Global Warming Potential (GWP) as the impact category for comparison purpose. A further comparison from student performance point of view has also been made at the end of the article. The result of this research shows that computer-based exams have least impact on the environment based on the selected GWP impact category as compared to paper-based exams. Furthermore, it has been found that there is no significant student performance difference in either type of these exams. read more... read less...
Keywords: LCA; Paper-based exam; Computer-based exam; Environmental impact
Experimental Investigation of Remote Vibration Sensing with Locally-Powered Devices
IJTEE, Volume-18, Issue 2 (2021) , PP 70 - 70
Published: 02 Sep 2021
DOI: 10.5383/ijtee.18.02.002
by Saeed k. Al Nuaimi, Manish K. Singh from Department of Mechanical and Aerospace Engineering, United Arab Emirates University, Al Ain, UAE and Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis MN 55455,USA
Abstract: Self-power sensors at multiple places in a network will be required for advanced wireless communication infrastructure, which comprises remote sensing technologies, networks, and data management. It is still difficult to power these sensors and their related transmitters or receivers. Local energy harvesting presents a chance to mitigate or eliminate the impact of this problem as an enabling technology. We create a self-powered real-time point-to-point wireless communication system, also known as transmission power self-optimization, that adapts the transmission power of a specific node in a wireless sensor network to the requirements. The transmitter module co-located with a vibrating object harvests and stores energy from vibration through piezoelectric components. Even when the vibrating source has very little energy, the collected energy allows for reliable wireless communication. The proposed system is discussed in detail, and data on voltage sensing, harvested power storage, and current are examined. read more... read less...
Keywords: Smart sensors; Energy harvesting;Internet of Things; Vibration sensing; Wireless transmission
RANS Based Numerical Simulation of Horizontal Axis Wind Turbine
IJTEE, Volume-18, Issue 2 (2021) , PP 57 - 63
Published: 02 Sep 2021
DOI: 10.5383/ijtee.18.02.001
by Liu Su, Isam Janajreh from Department of Mechanical Engineering, Khalifa University, Abu Dhabi, UAE
Abstract: A three-dimensional (3D) Computational Fluid Dynamics (CFD) model has been developed in this work to study 3.5kW Horizontal Axis Wind Turbine (HAWT). The model is based on the incompressible Navier-Stokes flow that accounts for the turbulence via SST k-ω turbulence model in a Single Rotating Reference Frame (SRF) that considers the rotor rotation. A body-fitted multi-block mesh is constructed around the turbine rotor with high-resolution mesh in the high-velocity gradient regions and in conjunction with the standard law of the wall next to the blade surface. The mod el comprises 4.5 million hexahedral elements; the blade is specifically wrapped in an O-grid boundary layer to achieve the desirable y+ value (<60). The flow around the blade was studied in detail (velocity, pressure, etc.) and results of the power coeffic ients were compared to the experimental data, which showed a plausible trend. The developed procedures can be easily and economically applied to any given HAWT configuration making the CFD a virtual wind tunnel in another complex atmospheric boundary layer flow. In view of these results, 2D blade mode is also developed and the power coefficient (Cp) values for the two models are compared. The results emphasized the role of rotation and radial momentum and demonstrated large discrepancies in the attained blade pressure values. read more... read less...
Keywords: CFD, HAWT, SRF, SST k -ω, Wall modeling
Investigating the Potential of Salinity Gradient Solar Pond as a Thermal Energy Storage System for Lahore Pakistan
IJTEE, Volume-18, Issue 2 (2021) , PP 101 - 105
Published: 23 Aug 2022
DOI: 10.5383/ijtee.18.02.006
by Muhammad Ali, Ussama Ali, Muhammad Tayyab Qureshi, Muhammad Lolak from The University of Lahore, Lahore, Pakistan and University of Engineering and Technology, Lahore, Pakistan
Abstract: This work is an attempt to experimentally study the ability of solar pond to store the thermal energy in the form of heat, and to explore the potential of solar energy and the prospects of solar ponds in Pakistan. A brief overview of the energy mix of Pakistan. Solar pond was built using a water tank of 300-galons. Halogen lamps were used to provide the heat and to resemble the sun’s radiations. The temperature of upper convective zone (UCZ) and lower convective zone (LCZ) was recorded for 100 hours. A maximum temperature of 66°C was recorded for LCZ, while that for UCZ was almost 40°C. Cyclic variations occurred in the temperature measurements of both zones which occurred with a time perio d of 24 hours which showed that the variation was due to the variants in the ambient weather conditions. This study provided short overview on the prospect of solar pond to store solar thermal energy which can then be utilized for various domestic/commercial activities. read more... read less...
Keywords: Solar thermal energy, Salinity gradient, Solar pond; Energy mix, Thermal storage